We Don’t Know Everything About Electric Fish

There are six different lineages of so-called “electric fish,” each of which evolved its potential independently and convergently. The most famous of these is the electric eel, though speaking of convergent evolution that species is not actually an eel. The portion of the body that produces the electric field is called the “electric organ,” and appears to be derived from muscle cells, but are quite different from each other. A recent paper in Science – “Genomic basis for the convergent evolution of electric organs” (pdf, press release) – investigating representatives of four of six lineages determined that, despite their differences, the same underlying genetic and cellular processes have been leveraged (or hijacked) in each case.

Nathaniel Jeanson has an article up today about this paper called “Darwin’s ‘Special Difficulty’ Solved?” His conclusion is, if anything, unusually weak, and it’s difficult to know what to make of it. He begins by quote-mining Darwin, a common tactic but one which the ICR doesn’t seem to often resort:

In Darwin’s seminal work On the Origin of Species he identified numerous examples of biological structures that, at first pass, seem very difficult to evolve. He even wrote a chapter titled “Difficulties on Theory” which he began with this wry comment: “Long before having arrived at this part of my work, a crowd of difficulties will have occurred to the reader. Some of them are so grave that to this day I can never reflect on them without being staggered.”

Long before having arrived at this part of my work, a crowd of difficulties will have occurred to the reader. Some of them are so grave that to this day I can never reflect on them without being staggered; but, to the best of my judgment, the greater number are only apparent, and those that are real are not, I think, fatal to my theory.

(Emphasis added to further highlight omission; all Darwin quotes in this post are from chapter six of On the Origin of Species.) As is well known, Darwin tended to build up the case for the opposition and then knock it down; this allows today’s creationists to selectively quote only the former portion and pretend for a moment that their arguments are not vastly out of date, long since refuted.

Jeanson then says:

One organ in particular that has dodged evolutionary explanation for over 150 years is the electric organ—the organ in fishes that generates electricity under water. Evolving this organ in one single species would pose serious challenges to evolution. But the organ is present in several fish species which, under the ancestry constraints imposed by the evolutionary interpretation of the fossil record, implies that the electric organ would have had to evolve, not once, but multiple times, making the naturalistic origin of this structure all the more implausible.

This is also a common creationist tactic, and one more often used: evolving a feature is extremely difficult/impossible/unlikely (because they said so), and so evolving it multiple times must be even harder (because obviously). An interesting counterpoint to this comes from the cryptic potentiating mutations in Lenski’s famous experiment, which lead to the repeatable evolution of aerobic citrate metabolism in lineages that possess them – it’s almost as if evolving a feature multiple times isn’t that much “harder,” so to speak, than doing it once.

Next, Jeanson quotemines Darwin again:

Darwin recognized this challenge early in his work in 1859. He wrote, “The electric organs of fishes offer another case of special difficulty; it is impossible to conceive by what steps these wondrous organs have been produced.” Nevertheless, he hypothesized a theoretical way over this hurdle: “As Owen and others have remarked, their intimate structure closely resembles that of common muscle.”

In fact, both of those quotes are part of the same sentence, but there’s even more than Jeanson reproduces. The full paragraph reads: (emphasis as before)

One of the gravest is that of neuter insects, which are often very differently constructed from either the males or fertile females; but this case will be treated of in the next chapter. The electric organs of fishes offer another case of special difficulty; it is impossible to conceive by what steps these wondrous organs have been produced; but, as Owen and others have remarked, their intimate structure closely resembles that of common muscle; and as it has lately been shown that Rays have an organ closely analogous to the electric apparatus, and yet do not, as Matteuchi asserts, discharge any electricity, we must own that we are far too ignorant to argue that no transition of any kind is possible.

The observation of a muscle-like structure has been more than confirmed in the years since – the cells are also seen to arise from muscle cells. It seems that in Darwin’s time he could already see an inkling of how the problem might be solved, and he observed that what was known at the time was hardly enough to declare with confidence that it could not have happened. A century and a half later Jeanson is in a much worse position to make that same declaration, and he only half-tries:

Could electric organs have evolved from mere muscle tissue? Since wholesale evolutionary change must ultimately stem from genetic changes, the first step in answering this question is investigating whether the diversity of electric organs could be produced via a common genetic pathway. Since Darwin knew nothing of genetics, he didn’t realize how big this difficulty really is. His ideas—his visualizations—were overly simplistic.

Genetics need not be the “first step” in such an investigation, and in saying so Jeanson erases basically all work before the present. You may also observe that, had Jeanson actually provided the full quote from Darwin above, he might have inadvertently revealed to his readers that Darwin was aware of his ignorance even if he could not contemplate its true magnitude. That evolution has survived the genetic revolution is widely considered a testament to its accuracy, and Jeanson can’t let this be acknowledged.

But it’s important to remember that there are two parts to this story: how the organs evolved, and how it could be that they did so multiple times. Jeanson only wants to talk about the former, but it is the latter that is the focus of the paper. On this second part Darwin wrote:

The electric organs offer another and even more serious difficulty; for they occur in only about a dozen fishes, of which several are widely remote in their affinities. Generally when the same organ appears in several members of the same class, especially if in members having very different habits of life, we may attribute its presence to inheritance from a common ancestor; and its absence in some of the members to its loss through disuse or natural selection. But if the electric organs had been inherited from one ancient progenitor thus provided, we might have expected that all electric fishes would have been specially related to each other. Nor does geology at all lead to the belief that formerly most fishes had electric organs, which most of their modified descendants have lost. The presence of luminous organs in a few insects, belonging to different families and orders, offers a parallel case of difficulty. Other cases could be given; for instance in plants, the very curious contrivance of a mass of pollen-grains, borne on a foot-stalk with a sticky gland at the end, is the same in Orchis and Asclepias, genera almost as remote as possible amongst flowering plants. In all these cases of two very distinct species furnished with apparently the same anomalous organ, it should be observed that, although the general appearance and function of the organ may be the same, yet some fundamental difference can generally be detected. I am inclined to believe that in nearly the same way as two men have sometimes independently hit on the very same invention, so natural selection, working for the good of each being and taking advantage of analogous variations, has sometimes modified in very nearly the same manner two parts in two organic beings, which owe but little of their structure in common to inheritance from the same ancestor.

The recent results amount to a confirmation of this concept, and more. But instead of talking about this Jeanson… makes another quotemine, as it turns out:

Realistically, the question of whether these organs originated via evolution does not rest on the commonality or differences among the electric organs’ genetic programs. Darwin did not cite developmental similarity as the gold standard test of evolution. Instead, in his “Difficulties with Theory” chapter he said, “If it could be demonstrated that any complex organ existed, which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down.” As Michael Behe has pointed out, this test can be taken only at the molecular level. Conversely, as Behe also highlighted, evolution is a failure if an organ—such as the electric organ—relies on mutually interdependent (irreducibly complex) molecular parts for its function.

The full Darwin quote is, of course:

If it could be demonstrated that any complex organ existed, which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down. But I can find out no such case. No doubt many organs exist of which we do not know the transitional grades, more especially if we look to much-isolated species, round which, according to my theory, there has been much extinction. Or again, if we look to an organ common to all the members of a large class, for in this latter case the organ must have been first formed at an extremely remote period, since which all the many members of the class have been developed; and in order to discover the early transitional grades through which the organ has passed, we should have to look to very ancient ancestral forms, long since become extinct.

The creationists – the “intelligent design proponents” especially – have conflated this with their “irreducible complexity,” a much less stringent designation. Indeed, Darwin begins his next paragraph by saying that “We should be extremely cautious in concluding that an organ could not have been formed by transitional gradations of some kind.” Jeanson has no basis in his own conclusion, but that’s not about to stop him.

He also declares that this is some kind of “gold standard test,” which apparently means that other considerations can be conveniently be discarded. In fact Darwin uses similar language to the above elsewhere:

If it could be proved that any part of the structure of any one species had been formed for the exclusive good of another species, it would annihilate my theory, for such could not have been produced through natural selection. Although many statements may be found in works on natural history to this effect, I cannot find even one which seems to me of any weight. It is admitted that the rattlesnake has a poison-fang for its own defence and for the destruction of its prey; but some authors suppose that at the same time this snake is furnished with a rattle for its own injury, namely, to warn its prey to escape. I would almost as soon believe that the cat curls the end of its tail when preparing to spring, in order to warn the doomed mouse. But I have not space here to enter on this and other such cases.

Creationists do point to altruism as evidence against evolution – though I’m yet to see a solid example that would apply here – but it’s quite clear that these tests do not have the status that Jeanson affords them. It may be that if some structure could be found that truly meets them evolution would be disproved, but that tells us nothing about how to prove evolution. That part Jeanson is ignoring, as it’s not going away – all he has is the long-shot possibility of a disproof.

With that in mind, he concludes:

To date, no one has comprehensively identified the relationships among the molecular components undergirding electric organ function. Until these relationships are elucidated, the plausibility of the evolutionary origin of these structures remains purely speculative and claims of evolutionary “fact” must be rejected because they are without scientific support.

In other words, because we don’t know everything about how these organs function Jeanson considers himself able to pretend that it didn’t happen. But remember what Darwin said (and Jeanson omitted): we certainly don’t have the evidence that would tell us that it didn’t evolve, quite the contrary. And anyway, as we learn more about the complexities of the process the ICR is only going to say that this means things are only more difficult, and that what was thought before was “overly simplistic.”

Peter, thanks for another good analysis. With each passing day ICR seems to be reaching new levels of sloppy reasoning and hypocrisy. The overarching point of Jeanson’s article–that we should discard a concept such as evolution, despite mountains of evidence for it, just because we don’t fully understand everything about it– is absurd. ICR has a large beam in its eye here, since mainstream scientists largely agree on the age of the earth, the major patterns of fossil succession, genetic and geologic principles, etc, and have massive amounts of evidence behind them, while YECs have nothing close to a comprehensive or consistent Flood model, and every one proposed to date severely contradicts the empirical evidence as well as other Flood models. I agree that the misleading quote mining in Jeanson’s piece was also especially blatant.

I have to wonder if this slippage from the ICR is real or perceived. Is it just that each new article only seems worse than the last, or are they really getting worse? I do know that a few years ago I tried to give their articles ratings, but it fell apart when it became apparent that there was no point giving them all an “awful” grade, or however it worked.

Given that “common design, common designer” is one of their favourite arguments, we should expect God to have used the same genetic tweaks to turn muscle cells into electric organs.

I’m willing to bet that at the genetic level, the mutations that lead to this change are very different even if they did happen within the same genes.

It seems to me that they will use this argument when it suits them (explaining genetic similarities between humans and chimpanzees) but then abandon the argument when they expect to find an embarrassing lack of similarity (as is the case in most examples of covergent evolution)

Peter, I agree it’s hard to say whether ICR’s articles are on average getting worse, since they’ve always bristled with scientific and logical errors. However, lately they just seem to cram in even more nonsense in than usual, and in the case of the URCall videos, into even smaller spaces. Some of the clips there consist almost entirely of false or illogical comments. Plus they are aimed at kids, which to me makes them even more disgusting. Maybe with the failure of their much touted “RATE” project, and their fading in prominence compared to AIG and other YEC groups, is making them more desperate to regain the spotlight or make themselves more relevant again; if so, it seems to be backfiring. Ironically, ICR declared the RATE project a resounding success, despite their being unable to give any scientific explanation the massive amount of radioactive decay in the geologic record. So they invoked ad-hoc miracles to produce vastly accelerated decay rates, then more unspecified miracles to protect the earth and all life from the massive heat (enough to vaporize the earth) such the acceleration would have caused –without explaining why God would accelerate decay rates in the first place, thus creating the lethal heat and making the earth look old, for no apparent reason. Heaven forbid they face the plain implications of the data: that YECism is fundamentally wrong. Astoundingly, the RATE authors acted like they saw no problem in their approach and conclusions, and apparently counted on most readers being unable to see them as well.

There is also an important point about these eels that Jeanson conveniently ignores: If all animals were originally vegetarians, as ICR and most YECs claim, then why do some fish even have an electric discharge system for stunning prey and warding off predators? It reminds me of the “Creation Moments” series by Creation.com, who publishes a daily email blurb supposedly demonstrating evidence for Creation. A large portion of their postings describe elaborate structures, systems, or behaviors various animals have to capture and kill prey, or defend themselves from predators. While implying they are “too well designed” to have evolved, it apparently never occurs to them that they contradict the YEC doctrine that there was no physical death (and thus no predation) before the Fall.
Some YECs suggest that God embedded in their genetic code the potential for extensive adaptation, but in many cases the amount of change necessary to explain the current appearances and lifestyles of various animals would have to be so extensive that they’d have had to turn into entirely different creatures. That would not only stretch YEC claims about the limits of microevolution, but also seem to contradict their belief Creation was essentially finished on Day 6. I’d like a YEC to explain, for example, how rattlesnakes, great white sharks, scorpions, and web-building, poisonous spiders were all originally “vegetarians.” Likewise, can any YEC explain why many insects are shaped and colored remarkably like leaves, sticks, etc. if there were no predators in the original Creation, and no significant evolution has occurred?

“Astoundingly, the RATE authors acted like they saw no problem in their approach and conclusions” According to friends of mine who know the RATE team members personally, there is nothing astounding about this at all.

By the way, as an indication of the credibility of the creationmoments.com website, they still trot out a number of lame claims long ago abandoned by most creationists, including the “moon dust” argument. They don’t refer to the Paluxy tracks (although one of their directors, Ian Taylor, who does their radio broadcasts, used to actively do so), they still claim “horse prints” are found in various Paleozoic rocks, saying, “Hoof prints have been found in Triassic, Pennsylvanian and Permian rocks that are supposedly much older than most of the dinosaurs.” However, the only reference cited says no such thing, but merely discusses some ambiguous crescent-shaped marks that are not in any walking pattern, and which are interpreted as likely invertebrate traces, While chiding evolutionists for supposedly hiding evidence, CreationMoments did not explain why the only source he cited was by conventional scientists; and why no YEC has ever rigorously documented any tracks of horses (or any other large modern mammals) in any Mesozoic or Paleozoic rocks (are they hiding evidence too?), despite the millions of dinosaur tracks, bones, and even eggs found in them.